Since the question is asking for her rate in Miles per hour. We want to convert the given time (minutes) to hours. 45 minutes is simply 3/4 of an hour, or 0.75 hours.
Now that we have how many miles she biked and how many hours it took, we simply divide the two values.
By converting 5 and 3/4 into a single fraction it would be 23/4, so we would divide 23/4 by 0.75 hours to get the final answer of 7.6667 miles per hour.
